Among various types of grill devices, waffle iron is a device particularly used for making waffle, which is made from a batter containing egg, flour, sugar, milk, etc. Examples of various types of waffles are Belgian waffle and Liege waffle. A conventional waffle iron includes a lower grill unit and an upper grill unit that are hinged together and that cooperatively define a cooking space therebetween. The upper grill unit includes an upper grill plate that is gridded. The lower grill unit includes a lower grill plate that corresponds in shape to the upper grill plate. Each of the lower and upper grill plates has a grill surface. To make a waffle, first the upper grill unit is pivoted upward, and a batter is poured onto the grill surface of the lower grill plate. Afterwards, the upper grill unit is pivoted downward to cover the lower grill plate, and the upper and lower grill plates are heated by heating elements of the upper and lower grill units for heating the batter to form a waffle.
During waffle making, usually the batter is randomly poured onto the lower grill plate, and the batter cannot spread quickly and evenly on the grill surface of the lower grill plate by itself. Furthermore, the fluidity of the batter decreases upon contacting the heated lower grill plate during pouring of the batter. Therefore, it is relatively difficult to obtain a waffle having a uniform thickness and without uneven edges.